Sealing high pressure flow devices

ABSTRACT

A fluid end assembly comprising a housing having multiple conduits formed therein. A tubular sleeve is installed within one of the conduits and is configured to house a plurality of packing seals. A seal is installed within a groove formed in the walls of the housing surrounding the tubular sleeve such that the seal engages an outer surface of the tubular sleeve.

BACKGROUND

This technology relates generally to sealing fluid flow passages insideflow control devices, such as those particularly suited for use in highpressure oil and gas production and processing systems.

For example, a fluid end is used in many well servicing applications tocontain high pressure, often corrosive and/or abrasive, fracturingfluids in the oil and gas industry. A fluid end typically has a manifoldbody and a number of components mounted and sealed to the body, such asthe suction and discharge plugs, suction and discharge valve seats,stuffing box, discharge flange, and suction manifold; with thosecomponents either alone or sleeved as are illustratively describedherein. Like the valves, operating a fluid end in the harsh oilfieldconditions can cause erosion of the body resulting in leakage in a shortamount of time. Repairing the body is also cumbersome and disruptive inthe oilfield.

Improvements are needed in the internal sealing of high pressure flowdevices to increase operating life while reducing downtime and operatingcost. What is needed is a solution that transfers the erosion (corrosionand abrasion) from the high pressure fluid end body to the componentsealed with the body. It is to those improvements that embodiments ofthis technology are directed as described in the illustrativeembodiments and contemplated within the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric depiction of a fluid end known in the art.

FIG. 2 is an enlarged depiction of a portion of the fluid end of FIG. 1.

FIG. 3 is an exploded cross-sectional depiction of an embodiment of afluid end.

FIGS. 4 and 5 are enlarged depictions of portions of the fluid end ofFIG. 3 .

FIG. 6 is a cross-sectional depiction of another embodiment of a fluidend.

FIG. 7 is an enlarged depiction of a portion of the fluid end of FIG. 6.

FIG. 8 is cross-sectional depiction of another embodiment of a fluidend. Another embodiment of a stuffing box sleeve is shown installedwithin the fluid end.

FIG. 9 is the cross-sectional view of FIG. 3 with the components showninstalled within the fluid end. A plunger and a plurality of packingseals are also shown installed within the fluid end.

FIG. 10 is a front perspective view of another embodiment of a fluidend.

FIG. 11 is a front elevational view of the fluid end shown in FIG. 10 .

FIG. 12 is a cross-sectional view of the fluid end shown in FIG. 11 ,taken along line A-A.

FIG. 13 an enlarged view of area A from FIG. 12 .

FIG. 14 is an enlarged view of area B from FIG. 12 .

FIG. 15 is a cross-sectional view of another embodiment of a fluid end.

FIG. 16 is an enlarged view of area C from FIG. 15 .

FIG. 17 is a front perspective view of another embodiment of a fluidend.

FIG. 18 is a rear perspective view of the fluid end shown in FIG. 17 .

FIG. 19 is a cross-sectional view of the fluid end shown in FIGS. 17 and18 , taken along line B-B.

FIG. 20 is a front perspective view of another embodiment of a sleeve.The sleeve is shown installed within the fluid end shown in FIG. 19 .

FIG. 21 is front elevational view of the sleeve shown in FIG. 20 .

FIG. 22 is a cross-sectional view of the sleeve shown in FIG. 21 , takenalong line C-C.

DETAILED DESCRIPTION

Initially, this disclosure is by way of example only, not by limitation.The illustrative constructions and associated methods disclosed hereinare not limited to use or application for sealing any specific assemblyor in any specific environment. That is, the disclosed technology is notlimited to use in sealing fluid ends as described in the illustrativeembodiments. Thus, although the instrumentalities described herein arefor the convenience of explanation, shown and described with respect toexemplary embodiments, the skilled artisan understands that theprinciples herein may be applied equally in sealing other types of highpressure flow devices.

FIG. 1 is a simplified isometric cross-sectional depiction of ahydraulic fracturing fluid end 200 that is constructed in accordancewith previously attempted solutions. The fluid end 200 comprises ahousing or fluid end body 201, which is generally a manifold used todeliver highly-pressurized corrosive and/or abrasive fluids, typicallyused in hydraulic fracturing processes in the oil and gas industry.Fluid may pass through the fluid end 200 at pressures that range from5,000-15,000 pounds per square inch (psi). Fluid ends 200 used in highpressure hydraulic fracturing operations typically move fluid at aminimum of 8,000 psi. However, normally, the fluid end 200 will movefluid at pressures around 10,000-15,000 psi.

The fluid end body 201 typically has a first conduit 220 and a secondconduit 221 formed within the body 201 that intersect to form aninternal chamber 222. The first conduit 220 is typically orthogonal tothe second conduit 221. The first conduit 220 may have aligned first andsecond sections 223 and 224 that are situated on opposite sides of theinternal chamber 222. The first section 223 may be referred to as adischarge bore, and the second section 224 may be referred to as anintake bore. Likewise, the second conduit 221 may have aligned third andfourth sections 225 and 226 that are situated on opposite sides of theinternal chamber 222. The third section 225 may be referred to as aplunger bore, and the fourth section 226 may be referred to as a suctionbore. The sections 223, 224, 225, and 226 each may independentlyinterconnect the internal chamber 222 to an external surface 227 of thefluid end 200.

A plunger 228 reciprocates within the fluid end body 201 to increase thepressure of fluid being discharged from the fluid end 200. As shown inFIG. 1 , the plunger 228 may be disposed within the third section 225 ofthe second conduit 221. The plunger 228 is disposed within a plungerpacking 213. The plunger packing 213 comprises a plurality of packingseals 219. The plunger 228 is powered by an engine operatively engagedwith the fluid end 200. In high pressure hydraulic fracturingoperations, the engine preferably has a power output of at least 2,250horsepower. Valve seats 229 are also shown supported within the firstconduit 220. The valve seats 229 may support valves, such as a ballvalve, used to control the movement of high pressure fluid within thebody 201.

There are sealing areas in the fluid end 200 that experience erosionduring operation. For example, a number of components seal to the fluidend body 201. As discussed above, the sacrificial member for erosion isthe fluid end body 201 instead of the less complex and less expensivemating component.

For example, the fluid end body 201 defines a discharge opening 202 thatopens into the discharge bore 223. The discharge opening 202 depicted inthese embodiments is sealed closed by inserting a closure or dischargeplug or cover 204 into the discharge bore 223 and securing it byadvancing a threaded retaining nut 206 into the body 201. The retainingnut 206 may also be referred to as a retainer. The discharge plug 204supports a seal 208 that seals against the walls of the fluid end body201 defining the discharge bore 223. FIG. 2 is a simplifiedcross-sectional depiction of the discharge plug 204 that has a groove207 into which the seal 208 is mounted.

In these illustrative embodiments the groove 207 is rectangular but thecontemplated embodiments are not so limited. The skilled artisanunderstands that the configuration of the groove 207 is largelydetermined by what shape is required to mount the type of seal selected.The groove 207 intersects an outer surface 215 of the discharge plug204, permitting the seal 208 to be sized so that a portion not mountedwithin the groove 207 extends beyond the outer surface 215 to pressinglyengage against the walls of the fluid end body 201 defining thedischarge bore 223. In this construction the highly-pressurizedcorrosive and/or abrasive fluid can be injected between the seal 208 andwalls defining the discharge bore 223, causing erosion of the sealsurface formed by the walls defining the discharge bore 223.

Fluid end bodies have conventionally been made of heat-treated carbonsteel, so it was not uncommon for the fluid end body 201 to crack beforeany sacrificial erosion of the body progressed to the point of creatingleakage between the discharge plug 204 and the discharge bore 223.However, progress in the technology has introduced stainless steel bodyconstruction resulting in a significantly longer operating life. As aresult, this erosion is no longer negligible but is instead aconsideration for reducing erosion in modern fluid end construction. Oneleading source of discharge bore 223 erosion in conventional fluid endsis the seal 208 mounted in the discharge plug 204 and extendingtherefrom to seal against a sealing surface formed by the fluid end body201. The technology disclosed herein is configured to transfer thaterosion wear from the fluid end body 201 to the less complex and lessexpensive discharge plug 204.

FIG. 3 is an exploded cross-sectional depiction of a fluid end 230having a housing or fluid end body 232. The fluid end 230 is constructedin accordance with the technology disclosed herein to, in numerousplaces, transfer the erosion wear from the body to the less complex andless expensive component that is sealed to the body. The fluid end body232 forms a number of interconnected bores or conduits, including afirst conduit 300. The first conduit 300 comprises a discharge bore 234and an intake bore 302 positioned on opposite sides of an internalchamber 304. The discharge bore 234 defines a discharge opening 235 thatis similar to the discharge opening 202 in the conventional fluid end200 depicted in FIG. 1 . Likewise, the intake bore 302 defines an intakeopening 231 formed opposite the discharge opening 235. The first conduit300 forms multi-dimensional diameters at different longitudinallocations between the discharge opening 235 and the intake opening 231.

The discharge opening 235 is sealed closed by inserting a closure ordischarge plug 236 into the discharge opening 235 and securing it inplace by advancing a threaded retaining nut 238, as shown in FIG. 9 .Unlike the conventional discharge plug 204 in FIG. 1 , the dischargeplug 236 does not have a seal mounted to it that seals against the wallssurrounding the discharge bore 234. Instead, the discharge plug 236defines a sealing surface 237 for a seal 242, shown in FIG. 4 . Thesealing surface 237 is axially spaced between a first surface 251 and anopposite second surface 253 of the plug 236. The seal 242 is mounted inan endless groove or recess 240 formed in the walls of the fluid endbody 232 surrounding the discharge bore 234, as shown in FIGS. 3 and 4 .

FIG. 4 is a simplified cross-sectional enlargement depicting theconstruction of the seal 242 positioned within the groove 240 formed inthe fluid end body 232. The groove 240 opens into the discharge bore234. The seal 242 in these illustrative embodiments is mounted in thegroove 240 to include an outer radial surface, and is thereby supportedby the fluid end body 232. The groove 240 is characterized by a pair ofparallel sidewalls 306 joined by a base 308. The groove 240 openstowards a centerline of the conduit within which it is formed.Alternatively, as shown by groove 266 in FIGS. 6 and 7 , the groove mayopen in a direction parallel to a centerline of the conduit within whichit is formed. As above, the rectangular shape of the groove 240 ismerely illustrative and not limiting of the contemplated embodiments.Any shape necessary to properly mount a desired seal is contemplated,whether the seal is elastomeric, spring, metal, and the like. The groove240 intersects the discharge bore 234 permitting the seal 242 to besized so that a portion of the seal 242 not contained in the groove 240extends beyond the groove 240 and beyond the bore 234 to pressingly sealagainst the sealing surface 237 defined by the discharge plug 236, asshown in FIG. 4 .

The seal construction depicted in FIG. 4 transfers the erosion wear fromthe fluid end body 232 to the discharge plug 236. Such transfer oferosion significantly improves fluid end operations because repairsinvolving the discharge plug 236 are significantly less complex and lessexpensive than repairs involving the fluid end body 232, which typicallyinvolve weld-repair. Furthermore, weld-repairing the fluid end body 232makes it susceptible to premature fatigue cracking in the repaired area.Further, even more operating life can be achieved by applying anerosion-resistant surface treatment to the discharge plug 236, such as ahigh velocity oxygen fuel (HVOF) treatment, a tungsten carbide coating,material carburizing, and the like. Replacing instead of repairing aneroded discharge plug 236 is typically feasible, making itadvantageously possible to repair a leaking valve constructed accordingto this technology in the field and thereby significantly reducing downtime.

Returning to FIG. 3 , another endless groove or recess 241 is formed inthe fluid end body 232. The groove 241 intersects the discharge bore 234and is configured to mount a seal (not depicted) that extends from thegroove 241 to seal against a sealing surface formed by a discharge valveseat, like the valve seat 229 shown in FIG. 1 . Similarly, anotherendless groove or recess 243 is formed in the fluid end body 232. Thegroove 243 intersects the intake bore 302 and is configured to mount aseal (not depicted) that extends from the groove 243 to seal against asealing surface formed by a suction valve seat, like the valve seat 229shown in FIG. 1 . The grooves 241 and 243 may be shaped identically tothe groove 240.

Continuing with FIG. 3 , the fluid end body 232 includes a secondconduit 310. The second conduit 310 includes a plunger bore 252 and asuction bore 247 positioned on opposite sides of the internal chamber304. The suction bore 247 is sealed closed by inserting a closure orsuction plug or cover 244 defining a sealing surface 245 and securing itin place by advancing a threaded retaining nut 246 within the body 232,as shown in FIG. 9 . Like the discharge plug 236, the sealing surface245 is axially spaced between a first surface 255 and an opposite secondsurface 261 of the suction plug 244. An endless groove or recess 248 isformed in the walls of the fluid end body 232 defining the suction bore247. The groove 248 may be construed identically to the groove 240. Thegroove 248 is configured for mounting a seal, like the seal 242 shown inFIG. 4 . The seal may extend from the groove 248 and seal against thesealing surface 245 of the suction plug 244. Such positioning transfersthe wear from the fluid end body 232 to the suction plug 244 incomparison to previously attempted solutions and in accordance with theembodiments of this technology.

Continuing with FIG. 3 , the plunger bore 252 defines a plunger opening250. The plunger bore 252 is sized to closely receive a stuffing boxsleeve 254 that is sealed in place by advancing a threaded retaining nut256, as shown in FIG. 9 . Because the sleeve 254 is secured within thefluid end body 232 by a retaining nut 256, no threads are formed in thesleeve 254 for mating with the fluid end body 232 or other component.Specifically, no threads are formed in an outer surface of the sleeve254 along a length of the sleeve 254.

The plunger bore 252 includes a first segment 312 and a second segment314. The first segment 312 is positioned closer to the internal chamber304 and the suction bore 247 than the second segment 314. The secondsegment 314 has a greater diameter than the first segment 312. Threadsmay be formed in the walls of the fluid end body 232 surrounding atleast a portion of the second segment 314. The threads may mate withthreads formed on the retaining nut 256. An endless groove or recess 257is formed in the walls of the fluid end body 232 surrounding the firstsegment 312. The groove 257 is configured to house a seal 260, as shownin FIG. 5 . The groove 257 may be identical to the groove 240. Likewise,the seal 260 may be identical to the seal 242.

Continuing with FIG. 3 , the stuffing box sleeve 254 is characterized bya tubular sleeve. The sleeve 254 comprises a first portion 316 joined toa second portion 318. The first and second portions 316 and 318 eachhave a cylindrical shape, such that the sleeve 254 may be consideredprimarily cylindrical. The first portion 316 has an outer diameter, D1.The second portion 318 has an outer diameter, D2. The diameter D2 isgreater than the diameter D1. The diameter D2 is also greater than amaximum diameter of the groove 257. The sleeve 254 is installed withinthe plunger bore 252 such that the first portion 316 is closely receivedwithin the first segment 310 and the second portion 318 is closelyreceived within the second segment 314, as shown in FIG. 9 . Thedifference between the diameters D1 and D2 and the diameters of theplunger bore 252 prevent further movement of the sleeve 254 into thefluid end body 232, as shown in FIG. 9 .

Continuing with FIGS. 3 and 9 , the diameter D1 is constant along atleast a portion of the length of the first portion 316 of the sleeve254. The diameter D1 may be constant along the entire length of thefirst portion 316, with the exception of a tapered surface 319 betweenthe first portion 316 and a first surface 322 of the sleeve 254. Nogrooves are formed in the outer surface of the first portion 316 forhousing a seal. Rather, the outer surface of the first portion 316 has asealing surface 259 for the seal 260, as shown in FIG. 5 .

The diameter D2 is constant along at least a portion of the length ofthe second portion 318. The diameter D2 may be constant along the entirelength of the second portion 318, with the exception of one or moregrooves formed in the outer surface of the second portion 318 forhousing a seal or receiving lubrication. The area of the outer surfaceof the sleeve 254 having the one or more grooves may be referred to as athird portion of the sleeve 254. An inner diameter of the third portionmay be the same as the inner diameter of the second portion 318.

FIG. 5 is a simplified cross-sectional depiction of the body 232 havingthe groove 257. Again, the groove 257 intersects the plunger bore 252permitting a portion including an outer radial surface of a radial seal260 to be mounted in the groove 257. Another portion of the seal 260 notmounted in the groove 257 extends from the groove 257 to pressingly sealagainst the sealing surface 259 of the sleeve 254. Although in thesedepicted embodiments a radial seal is used, the contemplated embodimentsare not so limited. The skilled artisan readily understands that othertypes of seals could be used instead of or in addition to the radialseal depicted, such as axial seals, crush seals, and the like.

Turning back to FIGS. 3 and 9 , the first and second portions 316 and318 of the sleeve 254 define a central passage 320. The central passage320 interconnects a first and second outer surface 322 and 324 of thesleeve 254. The first outer surface 322 may be joined to the firstportion 316 of the sleeve 254. The first outer surface 322 may be joinedto the outer surface of the first portion 316 via the tapered surface319. The second outer surface 324 may be joined the second portion 318or the third portion of the sleeve 254. The retaining nut 256 may engagethe second surface 324 of the sleeve 254, as shown in FIG. 9 .

Continuing with FIG. 3 , the first portion 316 has an inner diameter,D3. The second portion 318 has an inner diameter, D4. The diameter D4 isgreater than the diameter D3. The diameter D3 may be constant along thelength of the first portion 316, and the diameter D4 may be constantalong the length of the second portion 318, and if included, the thirdportion. An inner surface of the second portion 318 may transition to aninner surface of the first portion 316 at a right angle, such that aninternal seat 326 is formed within the second portion 318. Thetransition between the inner surface of the second portion 318 and theinner surface of the first portion 316 may be referred to as a firsttransition.

Similarly, an outer surface of the first portion 316 is joined to anouter surface of the second portion 318 at a right angle. In alternativeembodiments, the first portion may be joined to the second portion by atapered portion, as shown for example in FIG. 8 . The transition betweenthe outer surface of the first portion 316 and the outer surface of thesecond portion 318 may be referred to as a second transition. The firstand second transitions may also be referred to as a fourth portion ofthe sleeve 254.

Continuing with FIG. 9 , the plunger packing 213, including theplurality of packing seals 219, is installed within the second portion318 of the sleeve 254 such that the plunger packing 213 abuts theinternal seat 326. No portion of the plunger packing 213 is installedwithin the first portion 316 of the sleeve 254, as shown in FIG. 9 . Aportion of the plunger packing 213 may also be installed within thethird portion of the sleeve 254. The plunger 228 is disposed within atleast a portion of the sleeve 254 and the plunger packing 213.

FIG. 6 depicts another embodiment of a fluid end 330 comprising a fluidend body 332. A number of additional endless grooves or recesses areformed in the fluid end body 332 for mounting various seals to transferthe wear away from the body 332 to the mating component in accordancewith embodiments of this technology. For example, a groove 266 is formedin the fluid end body 332 intersecting a discharge bore 334. Consistentwith this whole description, the groove 266 permits mounting an axialseal 268, shown in FIG. 7 . The seal 268 is configured to extend fromthe groove 266 to seal against a leading face of a discharge plug, likethe discharge plug 236 shown in FIG. 3 . FIG. 7 is a simplified enlargeddepiction of the fluid end body 332 having the groove 266 into which theaxial seal 268 is mounted. In these illustrative embodiments the seal268 is configured to extend beyond the walls defining the discharge bore334 to seal against a discharge plug 236 as it is urged downward byadvancing a retaining nut, like the retaining nut 238, shown in FIG. 3 .

Importantly, the simplified seal construction depicted in FIG. 7 andelsewhere is in no way limiting of the contemplated embodiments andscope of the claimed technology. In alternative embodiments a radialseal or a crush seal and the like can be employed to transfer theerosion wear from the fluid end body 232 or 332 to the mating component.A crush seal refers to a seal construction that acts at least to somedegree both axially and radially. For example, a groove 272 having onlytwo walls is shown in FIG. 6 . The walls of the groove 272 extendconcentrically around a plunger bore 336. A stuffing box sleeve may beformed to have side walls that fully overlies the groove 272 when it ispositioned in the plunger bore 336, as shown for example in FIG. 15 .This allows the seal to act as a crush seal because it seals axially andradially against the installed sleeve.

Returning to FIG. 6 , the fluid end body 332 may have other surfacesforming endless grooves or recesses for mounting various other seals.For example, a groove 270 is formed in a suction bore 338 for mounting aseal that is configured to seal against a sealing surface of a suctionplug, like the suction plug 244 shown in FIG. 3 . In the same way thefluid end body 332 can have grooves 274 and 276 for mounting seals thatare configured to seal against sealing surfaces of a discharge valveseat and a suction valve seat, respectively. Likewise, the fluid endbody 332 can have a groove 278 for mounting a seal that is configured toseal against a suction manifold (not depicted). What's common in anyevent is the seal construction of this technology transfers the sealwear from the fluid end body 332 to the less complex and less expensivemating component that is attached to the fluid end body 332.

FIG. 8 depicts another embodiment of a fluid end 340 having a fluid endbody 342. The fluid end 340 is generally identical to the fluid end 330,but includes another embodiment of a plunger bore 344. The plunger bore344 is similar to the plunger bore 252, but is sized to receive anotherembodiment of a stuffing box sleeve 346. The stuffing box sleeve 346 isidentical to the stuffing box sleeve 254 with a few exceptions.

The stuffing box sleeve 346 comprises a first portion 348 joined to asecond portion 350 by a tapered portion 352. The first portion 348 isinstalled within a first segment 354 of the plunger bore 344 and thesecond portion 350 is installed within a second segment 356 of theplunger bore 344. A groove 358 is formed in the walls of the fluid endbody 342 surrounding the first segment 354. The groove 358 may beidentical to the groove 257. A seal 360 is shown installed within thegroove 358 and engaging an outer sealing surface of the first portion348. A seal 362 may also be installed within a groove 364 formed in anouter surface of the second portion 350 of the sleeve 346. Such area ofthe sleeve 346 may be referred to as a third portion of the sleeve 346.

As the stuffing box sleeve 346 is inserted into the plunger bore 344,air pressure forms in a space defined in the clearance gap between theouter diameter of the stuffing box sleeve 346 and the walls of the fluidend body 342 defining the plunger bore 344 and between the seal 360 andthe seal 362 at the opposing end of the stuffing box sleeve 346. The airpressure exerts a force urging the stuffing box sleeve 346 out of theplunger bore 344, complicating manufacture and degrading the sealintegrity at the lower end of the stuffing box sleeve 346. A breatheropening 284 can be formed between that space and ambient space above thestuffing box sleeve 346 to vent the air pressure.

FIG. 8 also depicts a conventional construction of the seal 362 that ismounted in the groove 364 formed by the stuffing box sleeve 346 andextends from that groove 364 to seal against the walls of the fluid endbody 342 defining the plunger bore 344. The contemplated embodiments caninclude combinations of the conventional construction and theconstruction of this technology where other matters come into play.

FIG. 8 also depicts employing the open-cylinder-shaped stuffing boxsleeve 346 and securing it in place by advancing a retaining nut, likethe retaining nut 256 shown in FIG. 3 . That construction isillustrative and in no way limiting of the contemplated technology.

Other configurations can be employed as well. For example, the skilledartisan understands that a conventional stuffing box can be employedthat combines a stuffing box sleeve and a retaining nut, unitarily, intoone component. In other conventional constructions, a stuffing box maybe used in combination with a seal carrier insert that mates with thestuffing box and provides the groove for mounting the seal. In yet othercontemplated embodiments, a stuffing box sleeve can be modified to aconstruction combining a substantially cylindrical-shaped stuffing boxto which is mated a seal surface insert that provides the sealingsurface.

Returning momentarily to FIGS. 3 and 9 , the sleeve 254 also protectsthe walls of the fluid end body 232 surrounding the plunger bore 252from erosion by providing an inner surface against which the plungerpacking 213 seals. That, again, by design transfers the wear from thefluid end body 232 to the less complex and less expensive sleeve 254.

With reference to FIGS. 10-14 , another embodiment of a fluid end 400 isshown. The fluid end 400 comprises a fluid end body 402 releasablyattached to a connect plate 404. The fluid end 400 is constructedsimilar to those embodiments described in United States PatentPublication No. 2019/0178243, in the name of Nowell et al., the entirecontents of which are incorporated herein by reference. The fluid endbody 402 and attached connect plate 404 may be referred to herein as thefluid end body or housing 406.

With reference to FIG. 12 , a first conduit 408 and a second conduit 410are formed in the housing 406. The conduits 408 and 410 intersect toform an internal chamber 412. As shown in FIGS. 10 and 11 , a pluralityof the first and second conduits 408 and 410 are formed in the fluid end400 and positioned in a side-by-side relationship. The first conduit 408includes a discharge bore 414 and an intake bore 416 positioned onopposite sides of the internal chamber 412. The second conduit 410includes a plunger bore 418 and a suction bore 420 positioned onopposite sides of the internal chamber 412.

Continuing with FIG. 12 , a discharge plug 422 is installed within thedischarge bore 414 and a suction plug 424 is installed within thesuction bore 420. The plugs 422 and 424 are retained within the housing406 using a plurality of retainers 426. Each retainer 426 is secured tothe housing 406 using a fastening system 428, like that described inUnited States Patent Publication No. 2020/0300240, authored by Nowell etal., the entire contents of which are incorporated herein by reference.

Like the discharge and suction plugs 236 and 244 shown in FIG. 3 , nogrooves are formed in the outer surface of the plugs 422 and 424 forhousing a seal. Instead, an endless groove 430 is formed in the walls ofthe housing 406 surrounding the discharge bore 414 for housing a seal432. Likewise, an endless groove 434 is formed in the walls of thehousing 406 surrounding the suction bore 420 for housing a seal 436.During operation, the seals 432 and 436 engage an outer sealing surfaceof the plugs 422 and 424. Over time, the seals 432 and 436 wear againstthe outer sealing surface of the plugs 422 and 424. If the outer surfaceof the plugs 422 and 424 begins to erode, the plugs 422 and 424 may beremoved and replaced with a new plug.

Turning to FIG. 14 , the groove 434 is characterized by two side walls440 joined by a base 442. The groove 240, shown in FIG. 4 , has two sidewalls 306 joined to the base 308 at a right angle or with small radiuscorners. For example, the radius corners may be approximately 0.015inches. In contrast, the groove 434, shown in FIG. 14 , has side walls440 joined to the base 442 via much larger radius corners 444. Theradius is approximately 0.150 inches. The larger radius corners 444 makethe groove 434 have a rounded cross-sectional shape. In operation, thelarger radius corners 444 help relieve stress in the walls surroundingthe groove 434, helping to increase the life of the fluid end 400. Inalternative embodiments, the radius corners may be even larger in size,such that the groove has the shape of a half circle. In furtheralternative embodiments, the walls forming the groove may have multiplesections with different radii.

Continuing with FIG. 12 , a stuffing box sleeve 446 is installed withinthe plunger bore 418. The stuffing box sleeve 446 is generally identicalto the stuffing box sleeve 254, shown in FIG. 3 , with a few exceptions.The sleeve 446 comprises a first portion 448 joined to a second portion450. The first and second portions 448 and 450 each have a cylindricalshape, such that the sleeve 446 may be considered primarily cylindrical.The first portion 448 has an outer diameter, D1. The second portion 450has an outer diameter, D2. The diameter D2 is greater than the diameterD1. The diameter D2 is also greater than a maximum diameter of a groove452 formed in the walls surrounding the plunger bore 418. The sleeve 446is installed within the plunger bore 418 such that the first portion 448is installed within a first segment 454 of the plunger bore 418 and thesecond portion 450 is installed within a second segment 456 of theplunger bore 418. The difference between the diameters D1 and D2 and thediameters of the plunger bore 418 prevent further movement of the sleeve446 into the housing 406.

Continuing with FIG. 12 , the diameter D1 is constant along at least aportion of the length of the first portion 448 of the sleeve 446. Thediameter D1 may be constant along the entire length of the first portion448, with the exception of a tapered surface 472, shown in FIG. 13 . Nogrooves are formed in the outer surface of the first portion 448 forhousing a seal. Rather, the outer surface of the first portion 448serves as a sealing surface for a seal 458, as shown in FIG. 13 .

The diameter D2 is constant along at least a portion of the length ofthe second portion 450. The diameter D2 may be constant along the entirelength of the second portion 450, with the exception of one or moregrooves formed in the outer surface of the second portion 450 forhousing a seal or for providing space for lubrication to be delivered tothe interior of the housing 406. The outer surface of the sleeve 446having the one or more grooves may be referred to as a third portion ofthe sleeve 446. An inner diameter of the third portion may be the sameas the inner diameter of the second portion 450, with the exception ofone or more lubrication holes.

The second portion 450 may further comprise one or more passages 451interconnecting the inner and outer surfaces of the second portion 450,as shown in FIG. 12 . The one or more passages 451 are in fluidcommunication with a lube port 453 formed in the housing 406. Duringoperation, lubrication is delivered to the interior of the sleeve 446via the lube port 453 and the one or more passages 451.

The first and second portions 448 and 450 of the sleeve 446 define acentral passage. The central passage interconnects a first and secondouter surface 460 and 462 of the sleeve 446. The first outer surface 460may be joined to the first portion 448 of the sleeve 446. The firstsurface 460 may join the outer surface of the first portion 448 via thetapered surface 472, shown in FIG. 13 . The second outer surface 462 maybe joined the second portion 450 or the third portion of the sleeve 446.A retainer 464 may engage the second surface 462 of the sleeve 446 andsecure the sleeve 446 within the plunger bore 418. The retainer 464shown in FIG. 12 is secured to the housing 406 using a fastening system,like that shown in United States Patent Publication No. 2020/0300240,authored by Nowell et al. In alternative embodiments, the retainer 464may thread into the walls of the housing 406.

Continuing with FIG. 12 , the first portion 448 has an inner diameter,D3. The second portion 450 has an inner diameter, D4. The diameter D4 isgreater than the diameter D3. An inner surface of the second portion 450may transition to an inner surface of the first portion 448 at a rightangle, such that an internal seat 466 is formed within the secondportion 450. The transition between the inner surface of the secondportion 450 and the inner surface of the first portion 448 may bereferred to as a first transition.

Turning to FIG. 13 , the inner surface of the first portion 448 may havea slightly convex portion 468 joined to a straight portion 470. Theconvex portion 468 may extend between the internal seat 466 and thestraight portion 470. Because the first portion 448 includes the convexportion 468, the first portion 448 may also have an inner diameter, D5.The diameter D3 is greater than the diameter D5. The convex portion 468helps increase the wall thickness of the first portion 448, which helpsalleviate stress within the sleeve 446 during operation. In alternativeembodiments, the inner surface of the first portion 448 may be shapedlike the sleeve 254 shown in FIG. 3 . The outer surface of the firstportion 448 may also include the tapered surface 472 adjacent the firstsurface 460.

Continuing with FIG. 12 , an outer surface of the first portion 448 isjoined to an outer surface of the second portion 450 at a right angle.In alternative embodiments, the first portion may be joined to thesecond portion by a tapered portion, as shown for example in FIG. 8 .The transition between the outer surface of the first portion 448 andthe outer surface of the second portion 450 may be referred to as asecond transition. The first and second transitions may also be referredto as a fourth portion of the sleeve 446.

Continuing with FIGS. 12 and 13 , the groove 452 is formed in the wallssurrounding the first segment 454 of the plunger bore 418. The groove452 is identical to the groove 434. In alternative embodiments, thegrooves 434 and 452 formed in the fluid end 400 may be shaped like anyone of the other grooves described herein.

Turning to FIGS. 15 and 16 , another embodiment of a fluid end 500 isshown. The fluid end 500 is identical to the fluid end 400, with theexception of its plunger bore 502. A groove 504 formed in the wallssurrounding a first segment 506 of the plunger bore 502 only has twoside walls 508 and 510, as shown in FIG. 16 . The side walls 508 and 510may intersect at a right angle or a radius corner.

Another embodiment of a stuffing box sleeve 512 is shown installedwithin the plunger bore 502. The sleeve 512 is identical to the sleeve446, but may have a shorter first portion 514 and a longer secondportion 516. When the sleeve 512 is installed within the plunger bore502, a base 518 of the second portion 516 forms a third wall of thegroove 504. A seal 520 installed within the groove 504 may be identicalto the seal 454, shown in FIG. 13 . During operation, the seal 520 wearsagainst an outer sealing surface of the first portion 514 of the sleeve512.

Turning to FIGS. 17-22 , another embodiment of a fluid end 600 is shown.The fluid end 600 comprises a housing 602 having an external surface 604and internal chamber 606, as shown in FIG. 19 . The housing 602 isshaped similar to that shown in FIG. 1 , in that it is of single-piececonstruction and includes a flanged portion 608. The flanged portion 608is configured to receive a plurality of stay rods used to attach thefluid end 600 to a power end. First and second intersecting conduits 610and 612 are formed in the housing 602. The first conduit 610 has firstand second sections 614 and 616, each of which independentlyinterconnects the internal chamber 606 and the external surface 604 ofthe housing 602. The second conduit 612 has third and fourth sections618 and 620, each of which independently interconnects the internalchamber 606 and the external surface 604.

Continuing with FIGS. 19-22 , the fluid end 600 uses another embodimentof a sleeve 622. The sleeve 622 is of single-piece construction andcomprises opposed first and second surfaces 624 and 626 joined by anouter intermediate surface 628. In contrast to the other sleeveembodiments disclosed herein, the outer intermediate surface 628 of thesleeve 622 has a constant outer diameter along the entire length of thesleeve 622.

The sleeve 622 defines a central passage 630 and has an internalshoulder 632 formed therein. The internal shoulder 632 is positionedcloser to the first surface 624 than the second surface 626 of thesleeve 622. A plunger packing 634 is installed within the sleeve 622through the second surface 626 until it abuts the internal shoulder 632.The plunger packing 634 comprises a plurality of packing seals 635.

Similar to the other sleeve embodiments disclosed herein, no grooves areformed in the outer intermediate surface 628 of the sleeve 622 forhousing a seal. Likewise, no threads are formed in the outerintermediate surface 628 for engaging the housing 602 or anothercomponent. The sleeve 622 may be made of steel, and not be coated withany abrasive material. If the sleeve 622 begins to erode over time, thesleeve 622 may be removed and replaced with a new sleeve.

Continuing with FIG. 19 , an endless groove 636 is formed within thewalls of the housing 602 surrounding the third section 618. The groove636 is positioned closer to the internal chamber 606 than the externalsurface 604 of the housing 602 and may be shaped like any of the endlessgrooves disclosed herein. An annular seal 638 is installed within thegroove 636. When the sleeve 622 is installed within the third section618, the seal 638 engages the outer intermediate surface 628 of thesleeve 622. Over time, the seal 638 wears against the intermediatesurface 628 of the sleeve 622. If the sleeve 622 begins to erode, it canbe removed and replaced with a new sleeve.

The housing 602 further comprises an internal shoulder 640 formed withinthe third section 618 between the groove 636 and the internal chamber606. Axial movement of the sleeve 622 within the third section 618 isprevented by engagement of the first surface 624 of the sleeve 622 withthe internal shoulder 640. When installed within the third section 618,no portion of the sleeve 622 projects from the external surface 604 ofthe housing 602.

The sleeve 622 is held within the third section 618 by a retainer 650.The retainer 650 has a threaded outer surface 652 and defines a threadedcentral opening 654. The threaded outer surface 652 mates with internalthreads 656 formed in the walls of the housing 602. When the retainer650 is installed within the housing 602 a first surface 658 of theretainer 650 abuts the second surface 626 of the sleeve 622, but theretainer 650 does not engage the plunger packing 634.

Continuing with FIG. 19 , a packing nut 660 having a threaded outersurface 662 is installed within the retainer 650. The threaded outersurface 662 of the packing nut 660 mates with the threaded centralopening 654 of the retainer 650. The packing nut 660 is turned withinthe retainer 650 until a first surface 664 of the packing nut 660engages and compresses the plunger packing 634. A reciprocating plunger670 is disposed within the packing nut 660, retainer 650, plungerpacking 634, and the sleeve 622.

In alternative embodiments, the housing 602 may be configured to use oneof the other embodiments of retainers disclosed herein. The othercomponents installed within the housing 602 and shown in FIG. 19 aresimilar to those disclosed herein.

In alternative embodiments, the sleeve may have different shapes andsizes but still function to form a second sidewall of the groove. Infurther alternative embodiments, the suction and discharge plugs may beconfigured to form one of the sidewalls of a two-walled groove formed inthe housing.

Summarizing, this technology contemplates a high pressure fluid flowapparatus constructed of a body defining a flow passage, a closuremounted to the body, and a means for sealing between the body and theclosure. For purposes of this description and meaning of the claims theterm “closure” means a component that is attached or otherwise joined tothe body to provide a high-pressure fluid seal between the body and theclosure. In some embodiments such as the described fluid end embodiments“closure” encompasses nonmoving components joined to the body to seal anopening such as but not limited to the discharge plug, suction plug,discharge valve seat, suction valve seat, stuffing box sleeve, dischargeflange, suction manifold, and the like. The term “means for sealing”means the described structures and structural equivalents thereof thatmount a seal to a body instead of a mating closure to transfer the wearin comparison to previously attempted solutions from the body to theclosure. “Means for sealing” expressly does not encompass previouslyattempted solutions that mount a seal to the closure to extend therefromand seal against the body.

The various features and alternative details of construction of theapparatuses described herein for the practice of the present technologywill readily occur to the skilled artisan in view of the foregoingdiscussion, and it is to be understood that even though numerouscharacteristics and advantages of various embodiments of the presenttechnology have been set forth in the foregoing description, togetherwith details of the structure and function of various embodiments of thetechnology, this detailed description is illustrative only, and changesmay be made in detail, especially in matters of structure andarrangements of parts within the principles of the present technology tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed.

1. A fluid end assembly, comprising: a housing having an externalsurface and internal chamber; a first conduit formed in the housing andhaving first and second sections, each section independentlyinterconnecting the internal chamber and the external surface; a secondconduit formed in the housing, intersecting the first conduit and havingthird and fourth sections, each section independently interconnectingthe internal chamber and the external surface; an endless groove formedin the fluid end housing and surrounding the third section of the secondconduit; a tubular sleeve installed within the third section, the sleeveof single-piece construction and having first and second surfaces joinedby an outer intermediate surface that extends along a length of thesleeve; in which the length of the sleeve is bounded by the first andsecond surfaces; in which the outer intermediate surface has a constantouter diameter along the length of the sleeve; in which no threads areformed in the outer intermediate surface of the sleeve; and in which nogrooves are formed in the outer intermediate surface of the sleeve forhousing a seal; an annular seal installed within the endless groove andengaging the outer intermediate surface of the sleeve; a plunger packinginstalled within the sleeve and abutting an internal shoulder formedwithin the sleeve; a retainer engaging the second surface of the sleeveand defining a threaded central opening; and a packing nut installedwithin the threaded central opening of the retainer and engaging theplunger packing.
 2. The fluid end assembly of claim 1, furthercomprising: a reciprocating plunger installed within the sleeve and theplunger packing.
 3. The fluid end assembly of claim 1, in which theendless groove is characterized by two walls joined by a base.
 4. Thefluid end assembly of claim 1, in which the retainer is attached to thehousing using a fastening system, the fastening system comprising aplurality of threaded studs.
 5. The fluid end assembly of claim 1, inwhich the retainer has a threaded outer surface.
 6. The fluid endassembly of claim 1, in which no portion of the sleeve is coated with anabrasive material.
 7. The fluid end assembly of claim 1, in which noportion of the sleeve projects from the external surface of the housing.8. The fluid end assembly of claim 1, in which the endless groove ispositioned closer to the internal chamber than the external surface ofthe housing.
 9. The fluid end assembly of claim 1, in which the annularseal is positioned adjacent the first surface of the sleeve.
 10. Thefluid end assembly of claim 1, in which at least a portion of theplunger packing is installed within the retainer.
 11. The fluid endassembly of claim 1, in which the internal shoulder is positioned closerto the first surface than the second surface of the sleeve.
 12. Thefluid end assembly of claim 1, in which the plunger packing comprises aplurality of packing seals.
 13. The fluid end assembly of claim 1, inwhich the annular seal is positioned between the first surface of thesleeve and the internal shoulder formed within the sleeve.
 14. The fluidend assembly of claim 1, further comprising: a first valve positionedwithin the first section of the first conduit; and a second valvepositioned within the second section of the first conduit.
 15. The fluidend assembly of claim 14, further comprising: a first valve seatpositioned within the first section of the first conduit, the firstvalve configured to seal against the first valve seat; and a secondvalve seat positioned within the second section of the first conduit,the second valve configured to seal against the second valve seat. 16.The fluid end assembly of claim 1, in which the endless groove ischaracterized as a first endless groove and the annular seal ischaracterized as a first annular seal, the fluid end assembly furthercomprising: a second endless groove formed within the fluid end housingand surrounding the first section of the first conduit; a discharge plugpositioned within the first section of the first conduit; and a secondannular seal installed within the second endless groove and engaging anouter surface of the discharge plug.
 17. The fluid end assembly of claim1, in which the endless groove is characterized as a first endlessgroove and the annular seal is characterized as a first annular seal,the fluid end assembly further comprising: a second endless grooveformed within the fluid end housing and surrounding the fourth sectionof the second conduit; a suction plug positioned within the fourthsection of the second conduit; and a second annular seal installedwithin the second endless groove and engaging an outer surface of thesuction plug.
 18. The fluid end assembly of claim 16, furthercomprising: a third endless groove formed within the fluid end housingand surrounding the fourth section of the second conduit; a suction plugpositioned within the fourth section of the second conduit; and a thirdannular seal installed within the third endless groove and engaging anouter surface of the suction plug.
 19. The fluid end assembly of claim15, further comprising: a retainer attached to the housing and engagingthe discharge plug.
 20. The fluid end assembly of claim 16, furthercomprising: a retainer attached to the housing and engaging the suctionplug.